Smoke detector and signal



July 26, 1949. c. N. CAHUSAC ETAL 2,476,958

SMOKE DETECTOR AND SIGNAL 7 Filed Sept. 28, 1946 3 sheets-Sheet 1 INVENTORS W a. W,

BY M

A'rroR/vEY July 26, 1949. c. N. cAHusAc ETAL 2,476,958

SMOKE DETECTOR AND SIGNAL Filed Sept. 28, 1946 3 Sheets-Sheet 2 luvs/Violas 7'4T TOR NEV w s S R R R mm Q MW QN E N 5% s .Q m B NF \N, N I) \w w m r p F ,l w E R J|.l r. R\W(Wz/ 1 m a N U I RM. u U Ww NQ LWM Q sw m WW i fi w xvu w July 26, 1949. c. N. cAHusAc ETAL 2,476,958

SMOKE DETECTOR AND SIGNAL Filed Sept. 28, 1946 s Sheets-Sheet s INVENTORJ %%NEY Patented July 26, 1949 2,476,952; SMOKE DETECTOR SIGNAL eie i Fee s-Be m iiex lla i i l i tion of Delaware Diehl, Arlington, N. J., a s igno1 s= to gogr wo ire Equipment 00., Newark; NJIL; a corpora.-

Ap neanon September 28, 154i, senile. 7 06, 651) 3 Claims. ((21. 25011115) i nt n s inc e f apparatus fijqet tieea d an oun inethe existence, at apqin cj emoteifromk ther li a h a fluid having particles oirn atter, such as smoke, suspended therein and the invention ,relatesto that disclosed 11111116 copengiingapplication of Clarence liolel Qanusac and Frank B.,All en, Serial No. 604,892, filed July ,13, 1 945, which. is especially dapted .io ncletectinemt e esence f smo e n the various compartments of an aeroplane or the 1i1:l (-3, and fqr prqducingna signalfor example on instrument board-:to insure. immediate warning of fires and prompt action to extinguish hemc. .v .c In genera1, theapparatus comprises means for producing a beam of 'light, means for, conducting a stream of finid suchas smoke, into said light beam, a phqtoelectric; element of the generative type located witn respectpto said beam and said fluid stream to receivelightrays reflected from suspended matter in, g id, fluid. stream, another photoelectric element located to receive light rays transmitted through said fluid stream, means connecting said jphotoelectric elements in an elec ric circuit whereby the photoelectric effects o f the se cgndgnentioned element opposes the photoelectric effects offlrthe, first-mentioned element and anel'e'ctrical responsive 'means,- such a relay, in saidhcircuit 'for controlling the production vo; an audible or visible signal;

Mea ns also included tor varying at will'the extent of egip qsure of the second-mentioned photoelectric ele nent to the light rays, With this arrangement bv adjustment of the means for varying tneegteht exposure-of, the seconds mentioned Plfl tb1ctirib element to the light ray-S} new q vth ii j beet fifstminvtimd lemntmay-b hee by photoele tri v eflfect of th; light 611, the I second mentioned photoelectric element whereby asteady and nor mal setting of the electrical resbons e device mav eottein d T la te e'otviat th necessity" of a voltage regulating apparatus ran s o ctes m the resetting the electrical responsive device after nytqnere iuno ihe ap ara us .AilQthfi a ect.ist qp qv de S 1 1 fneceiid. nese tin omet anis whi h. shal embqsiyi new nd immeiecl ieat rse me han ca .a dd r trieal cconst M g: electrig element rnay p e utilized for both testing nd perations-c.

e t to pr de, in. appar tus pf ove Jam l-impr ed constrec: W. e i nhei ihl h ie rr t e im the ee np n zee ll at ren ws-whe by, he eliest not he gh 97911 t li ht n n th h a i r. ing ce ll shall be rcapable of easy and accurate other iep epeeyeii. a s and esultseefnt e le lt qeewill the; br ught 9 4 bx the. .q11p.wine descrintipninconjunction with the accompany- V n a r 1'. Figur .is a sigie ele ati nal view of a smoke t i9r..- nl ad ie Qu c even n-l ,v c 7. F lire 2 is an elevational view of one end ,3. .i n; :'.I1'.. ,1; :Q Me i a-,3 ipr z ntalt one V w npfmxi: m re 9 the fia Qit l n 3 11 F -e4 i @IfiGQ n tu al,s ctional.

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.c ills eir fiientam ra er ve t ca sectional View taken approximately on the plane thev cie fiffie vliieie fizand. Figure; is a wiring diagram of e the electrical circuit c for the n ke detector. andnsignall -;.$I?ifi jibine the illustrated emb e l ml t pnz. he e enc cha cter L?! ll. e sin i t a de tinenunit ie ebl hesnetn east @neside Wall, 2 he end alls 3 re ovalole for access, ..t0 ,xthe pa s in the. casing, vany suita ble separable false, provided for connecting said side ,in j ta. Ql compartm nt v.li.

Tiqs l h source 8, such; it c e e et lc a pkfia drcompartment 15.. heyieerppex ines .rtlquvres .9,for,passageof an through the compartment. The side, bottom and top walls of the smoke compartment 6 also have I louvres ID for the circulation of smoke into and through the compartment. These louvres are. so constructed as to prevent the entrance of light into the casing in any such manner as to effect the photoelectric cells therein, and one satisfactory type of louvre is disclosed in a copending application of Clarence Noel Cahusac and Frank B. Allen, Serial No. 619,744, filed October 2, 1945.

In the partition 5, is a lens system H through which the light rays from the lamp 8 are directed into and longitudinally of the smoke compart ment 6, so that said rays (represented by broken lines) are projected in a parallel beam through said compartment,

At least one photoelectric element l2 isadjustably mounted on a bracket 13 at one side of the light beam so as to be sensitive to thelight rays reflected from the suspended matter in the fluid entering the casing. This photoelectric element may be of any suitable type, such as the current generating barrier layer type, and preferably has a large flat rectangular exposed light-sensitive surface 14 and is capable, of generating sufficient current to operate a relay without amplification of the electricity. I

The light-sensitive surface is exposed in close proximity to the outerboundaries of the light beam and is tilted obliquely with respect to the light beam so that said surface is inclined away from the light source as shown in Figure 2, whereby greater sensitivity is obtained and the effect of stray light rays, when no smoke is present in the compartment, is substantially reduced. As shown, the bracket 13 comprises an angular strip of metal l5,'on one flange of which the cell [2 is mounted by adjustable screws l6, while the other flange is tiltably connected, as by a screw ll, to

'thebase portion of a U-shaped support [6, the

arms of which are rigidly secured to one side wall of the casing in any suitable manner, for example soldering, as indicated at l9. 7

' The photoelectric element I2 is connected in circuit with any suitable electric responsive device, for example a micro-ammeter, or, as shown, a relay 26 which may be mounted by a frame 2 I on a transverse partition '22 in the casing forming the endof the smoke compartment 6 opposite the lens system, the face of the relay being exposed and visible through an opening 23 in the corresponding end wall of the casing. This relay controls another circuit which may include any desired electrically operated device, such as a signal lamp 24, located on the instrument panel 25, generally indicated by the broken lines in Figure 7 which is a diagram showing the circuit for the relay, a source of electricity, the photoelectric elements and the signal.

Another photoelectric element '26, which may be ofthe' same general type as the element l2, is mounted by bolts 21 on a U-shaped bracket 28 that extendstransversely of the casing and has its 1 arms rigidly secured as by screws 29 to the bottom wall of the casing. The light-sensitive surface of said cell 26 faces downwardly toward and is spaced from the bottom wall of the casing as best shown in Figures 4 and 5, so as to be subject to light rays passing from the light source 8 through an opening 38 in the partition 5, and is reflected from the bottom wall of the casing onto the cell. Pref: erably, a transparent or translucent plate 3| is disposed across the opening 30 to protect the cell from the heat of the lamp, to diffuse the light and v to prevent smoke entering the lamp compartment. To varyithee'xtent of exposure of the photoelectric element 26 to said reflected light rays, a shutter or bafile 32 overlies the light-sensitive surface of the cell and has connected thereto a nut 33, through which is threaded a screw 34, one end of which is rotatably mounted in a bracket 35 that is secured to the bottom wall of the casing.

As shown, this screw 34 has a coupling element 36 at one end for connecting the screw to an operating shaft 31 which is rotatably mounted in and extends through the end Wall of the casing adjacent the relay 20. The outer end of said shaft has connected thereto an operating element 38 which is rotatably mounted in the casing wall and has a kerf 39 for a screw driver, or other suitable means, to permit rotation of the shaft. This shaft is longitudinally non-movable.

With this construction it will be observed that by rotating the element 38, the screw 34 will be rotated so as to move the. shutter 32 in such a way as to expose more or less of the light-sensitive surface of the cell 26 as indicated by solid and 'dot-and-dashilines in Figure .4, the solid lines showing the shutter in the position to completely cover the light-sensitive surface.

The photoelectric element '26 is connected in circuit with the photoelectric element l2 and the relay 26 in what is known as an opposed paralle arrangement, or so that the photoelectric effects of said elements are caused to operate in compensatin differential or'opposing relation; in

other words, the electrodes of the element 26 are connected respectively to the opposite electrodes of the element l2 (see Figure '7).

With this construction, initially, the photoelec tric cell circuit is so adjusted that-the relay or other device 26 will assume a normal condition, for exampleto-o'pen the signal circuit when-n0 smoke is present in the compartment 6, and when smoke or other fluid, containing susp nded matter, is caused to flow through the casing into the beam of light, some of the light rayswill be reflected from the solid particles in the stream upon the photoelectric celll2, whereupon the relay'or other device 20 will be actuated by the current in the photoelectric cell circuit.

In the specificirelay 20 illustrated in the draw ings, there is'a pointer or swingable contact arm 30 which is responsive to current in the photoelectric cell circuit and normally is spaced from a fixed contact 4|, but is actuated into engagement with said contact when the photoelectric cell circuit is energized as shown in Figure 6.

It will be observed that the cells l2 and 26 will be continuouslysomewhat aifected by stray light rays from the beam even when no smoke is present in the compartment, and the cells will be steady operation of the relay.. By adjusting-the shutter 32 when no smoke is present'in the com-' partment 6, the effect of the light on'the cell l2.

may be balanced by the effect of the light on the cell 26 to insure a steady and normal setting of the relay pointer 40. l

When the relay is energized by electricity gen erated by the photoelectric cell I2, its contact arm 4|! engages thecontact 4I and tends to remain in.

such contact. It is customary to provide means for resetting this contactarm from anydesired remote point. For the purpose of illustration, we

have shown a resetting rod 42 slidably mounted in a suitable bearing 43, and having ,a head 44 normally in spaced relation to the contact arm 4!! when the latter engages the contact H as sli'l'i'vlrn in- Figure 6: For so holding the head 44, a compressionspring 451s interposed between the bearing 43" and a collar 46- on the rod, and said spring also holds the end'ofthe" rod 42opposite tfie he'ad M in' abutting contactwith a flange 4-1 which-is connect-ed to'an arm 4 8 on an armature lever 4'9 that is actuated by an electromagnetic coil 50 that is iil r-turn?carried bya bracket 51 secured on an arm 52 projecting from the fram'fl'. w H

Normally, the spring 45 holds the lever 49 in spaced relation to the e'lectromagheticcoil and movement of the lever under the influence of the spring is limited by a stop arm 53 on the bracket 5|.

In accordance with the invention, we provide a switch mechanism operated by the same finger piece for both resetting the contact arm 40 of the relay and testing the apparatus to ascertain whether or not the photoelectric cells and the circuit are in operative condition. As shown, the electromagnetic coil 59 is connected in the electric circuit with a normally open switch which includes a fixed contact 54 and a movable contact 55 that is mounted on a spring arm 56 which in turn is actuated into switch-closing position by an operating lever or finger piece 51 that is pivotally mounted at one end, as indicated at 58,

and will bear against the free end of the spring tion of the armature lever 49 so as to push the resetting rod 42 with a snap action against the contact arm 40 which thereby will be pushed back to its normal position against a zero stop pin 59.

The same switch-operating lever or finger piece 57 is utilized for operating the switch for testing the photoelectric cells and the circuit generally. This switch is shoWn as comprising a fixed contact 60 with which cooperates a movable contact 6| that is mounted on a spring arm 62 so that the contacts 66 and 6| are normally engaged in circuit-closing position. These two contacts are connected in the circuit so that when they are disengaged to open the circuit, the balancing photoelectric cell 25 is thrown out of the circuit while the main photoelectric cell I2 remains operatively connected in circuit with the operating coil 63 of the relay 29. When the balancing cell is thrown out of the circuit, the opposing effect thereof on the main cell I2 is eliminated and, consequently, said cell will be actuated by the light rays in the smoke chamber 6 even when no smoke is present. When the cell so operates, it is indicative that the whole system is in operative condition. Should the cell not operate in this manner, it would be apparent that something is Wrong in the circuit.

It will be apparent that the contact 6! may be moved away from the contact 6!! by movement of the operating lever or finger piece 51 against the spring arm 62 in the direction opposite to that in which the finger piece is moved to operate the spring arm 56 of the resetting switch. As shown, the finger piece or operating lever 51 may conveniently be located between the two spring arms 56 and 62, but other arrangements will occur to those skilled in the art.

In order to prevent or restrict reflection of the light rays in the light beam from the partition 22, we utilize a piece of light-absorbing material, preferably a piece of pile fabric such as plush Cal 6-4; which maybe secured at the outer side-of the partition by the same screws seamen can:

modifications and changesin: the details or con struction'of the apparatus maybe made Within the spirit and scope of the-invention.

The apparatus for detecting suspended matter in a fluid is claimed in co-pending applications owned by a common assignee, Serial Number 619,744 filed October 2, 1945, and Serial Numbers 74,341 and 74,342 filed February 3, 1949, as continuations-in-part of application Serial Number 604,892, in turn, filed July 13, 1945, and which issued as Patent 2,464,211 on March 15, 1949.

We claim:

1. The combination with a photoelectric system wherein there is a light source, two photoelectric elements of the generative type responsive to light from said source, means for varying the effect of light from said source upon one of said cells, means connecting said photoelectric elements in a circuit so that the photoelectric efiects of one of said elements opposes the photoelectric efiect of the other element, and electrically responsive indicating means in said circuit, of a normally closed switch in said circuit which when opened will out One of said photoelectric elements out of said circuit so that said indicating means will be responsive only to the effect of light upon the other photoelectric element, for testing the integrity of the photoelectric elements and said circuit.

2. Apparatus for detecting suspended matter in a fluid, comprising means including a light source for producing a beam of light, a photoelectric element of the generative type responsive to light from said beam, means for conducting a stream of such fluid into said light beam to vary the eiiect of said light on said photoelectric element, a second photoelectric element responsive to light from said source relatively independently of the effect of said stream of fluid, means connecting said photoelectric elements in an electric circuit so that the photoelectric efiects of said second photoelectric element opposes the photoelectric efiects of the first-named photoelectric element, and electrical responsive means in said circuit, and a normally closed switch in said circuit which when open will out one of said photoelectric elements out of said circuit whereby said responsive means will be responsive only to the efi'ect of said light rays on the other photoelectric element and regardless of the presence of said fluid stream.

3. A combination as defined in claim 1, wherein said electrically responsive indicating means comprises a relay connected in circuit with a source of electricity and including a fixed contact and a movable contact arm which in normal position is spaced from said contact to open said relay, means in said photoelectric circuit by which said movable contact arm is electrically swung into engagement with said contact to close the relay, and with the addition of an electrically operated resetting mechanism for said movable contact arm, a second switch for controlling said resetting mechanism, and a common finger-piece for operating said switches selectively to cut out sald photdeiectrie element and to reset said movable arm, respectively.

CLARENCENOEL CAHUSAC. DONALD A.'DIEHL.

REFERENCES CITED 7 The following references are of record in th file qt this patent:

UNITED STATES PATENTS Number 7 Name Date 1,794,686 Heinisch et a1. Mar. 3, 1931 1,828,894

Freygang Oct. 27, 1931 Number Number Germany 'Nev. 20, 19.31 

